NMR resonator configured as an insulated foil, conductively coated on both sides

Abstract

A nuclear magnetic resonance (NMR) resonator ( 1; 31 ) comprising an inductive section ( 6 ) and a capacitive section ( 6 a ), wherein the inductive section ( 6 ) is band-shaped and surrounds a substantially cylindrical volume under investigation ( 5 ), wherein the capacitive section ( 6 a ) is formed from one or more discrete capacitor(s) ( 13; 13 a, 13 b, 13 c, 13 d ), and wherein the ends ( 7, 8 ) of the band-shaped inductive section ( 6 ) are connected through one or several capacitor(s) ( 13; 13 a, 13 b, 13 c, 13 d ) of the capacitive section ( 6 a ), is characterized in that the inductive section ( 6 ) is formed from a dielectric flexible foil ( 2 ) which is conductively coated on both sides and the ends ( 7, 8 ) of the band-shaped inductive section ( 6 ) overlap, wherein the outer coating ( 4 ) of the inner end ( 7 ) is electrically conductingly connected to the inner coating ( 3 ) of the outer end ( 8 ), with one or more through-connections ( 10 ) being provided in the area of the inner end ( 7 ) of the band-shaped inductive section ( 6 ), and the outer coating ( 4 ) being connected in the area of the outer end ( 8 ) to the inner coating ( 3 ) in the area of the inner end ( 7 ) via one or more capacitor(s) ( 13; 13 a, 13 b, 13 c, 13 d ) and one or several through-connection(s) ( 10 ). The inventive NMR resonator for low-resolution NMR has a simple construction and provides NMR measurements of improved quality at low resonance frequencies.

1. A nuclear magnetic resonance (NMR) resonator comprising:
 a flexible dielectric foil having a first end region and a second end region, said foil rolled into a substantially cylindrical shape such that said first end region overlaps with and is radially outside of said second end region, said foil constituting an inductive section, wherein said foil has at least one through-hole extending through said foil at said second end region; 
 a first conductive coating disposed on an outside of said foil; 
 a second conductive coating disposed on an inside of said foil; 
 means for electrically connecting said second conductive coating at said first end region to said first conductive coating at said second end region; and 
 at least one discrete capacitor connected between said first conductive coating at said first end region and said second conductive coating at said second end region via said through-hole to form a capacitive section. 
 
   
   
     2. The NMR resonator of  claim 1 , wherein a resonator frequency of the NMR resonator is within a range of between 1 MHz and 100 MHz or between 5 MHz and 20 MHz. 
   
   
     3. The NMR resonator of  claim 1 , wherein said flexible foil is produced from Teflon. 
   
   
     4. The NMR resonator of  claim 1 , wherein said first and said second conductive coatings of said foil are free from ferromagnetic material. 
   
   
     5. The NMR resonator of  claim 1 , wherein said first and said second conductive coatings of said foil contain copper and/or silver. 
   
   
     6. The NMR resonator of  claim 1 , further comprising a protective cover disposed on said first and said second conductive coatings. 
   
   
     7. The NMR resonator of  claim 1 , wherein a volume under investigation has a volume in a range between 0.1 cm 3  and 10 cm 3 . 
   
   
     8. The NMR resonator of  claim 1 , wherein a number of through-holes is between 3 and 10. 
   
   
     9. The NMR resonator of  claim 1 , wherein the NMR resonator is designed such that RF current is axially distributed to said inductive section during operation, wherein an RF current density in axially outer areas of said inductive section is increased with respect to an axially inner area. 
   
   
     10. The NMR resonator of  claim 9 , wherein a distribution of RF current is adjusted by means of a corresponding axial distribution of positions of through-holes and through-connections and/or a corresponding axial distribution of capacitance values of said at least one capacitor, and/or a corresponding axial distribution of partially circumferential slots in said first and said second coatings. 
   
   
     11. The NMR resonator of  claim 1 , wherein said foil and said first and second coatings are produced as a printed circuit. 
   
   
     12. The NMR resonator of  claim 11 , wherein said printed circuit comprises coupling structures for coupling RF energy in and/or out. 
   
   
     13. The NMR resonator of  claim 12 , wherein said coupling structures are formed in an axial edge area of said foil. 
   
   
     14. The NMR resonator of  claim 13 , wherein said coupling structures are formed largely symmetrically at both axial edge areas of said foil. 
   
   
     15. The NMR resonator of  claim 12 , wherein said coupling structures comprise strip conductors on both sides of said foil. 
   
   
     16. The NMR resonator of  claim 1 , wherein a material of said flexible foil and a thickness of said flexible foil and a material of said first and said second coatings and a thickness of said first and said second coatings are selected such that the NMR resonator is self-supporting. 
   
   
     17. A low-resolution NMR spectrometer comprising the NMR resonator of  claim 1 .